Naomi Mandel, an associate marketing professor at ASU, has been researching the relationship between body size and marketing and found that using chubsters in ad campaigns lowers womens' self-esteem and makes them less likely to buy a product.

"We believe it is unlikely that many brands will gain market share by using heavy models in their ads," Mandel says. "We found that overweight consumers demonstrated lower self-esteem -- and therefore probably less enthusiasm about buying products. Also, normal-weight consumers experienced lower self-esteem after exposure to moderately heavy models, such as those in Dove soap's 'Real Women' campaign, than after exposure to moderately thin models."

Similarly, the use of emaciated, bulimic-looking beauties in ad campaigns could potentially make women develop an eating disorder, Mandel's research found.

That being the case, would throwing Kate Moss in a Weight Watchers ad cause women to lose weight without even buying the product?